At SXSW this afternoon, Makerbot founder Bre Pettis unveiled a prototype of the company's first 3D scanner, the Digitizer. From a user perspective, the scanner seems straightforward. You place the object to be scanned on a revolving pedestal, then its dimensions are captured with a combination of lasers and cameras. Pettis pitched the Digitizer as a device anyone can use to create a 3D model suitable for printing, without requiring any CAD or 3D modelling experience.
Beyond the basic theory, there isn't a ton of information--Makerbot's Digitizer page is just a front-end to notify you when there's more information available. We know that Makerbot has been experimenting with 3D scanning for at least 2 years--I was 3D scanned at Bay Area Maker Faire in 2011.